GMC Sierra 4WD is a full-size pickup truck manufactured by General Motors. It was introduced in 1998 as the successor to the GMC C/K pickup truck line. The Sierra is available in two-wheel and four-wheel drive configurations, with optional trim packages that include the Denali, All Terrain, and SLT. The engine options range from the 4.3-liter EcoTec3 V6 to the 6.2-liter EcoTec3 V8, both of which are capable of towing up to 12,500 pounds.